Field of the Invention
The invention relates to gas turbine engines in particular for use in the aeronautical field.
Description of the Related Art
A gas turbine engine intended to be fitted on an aircraft conventionally includes a plurality of parts which are connected to one another by fixings of different types such as flanges. In some configurations, two parts of the engine can be made to slide against one another along their contact surfaces due to thermal expansion. By way of example, a low-pressure distributor of a gas turbine engine includes a plurality of metal blades which are mounted in a fixed manner in the metal housing of the engine. To this end, each blade includes a lower platform and an upper platform which are shaped so as to be fixed respectively to a lower housing element and to an upper housing element of the engine. During the operation of the engine the platforms of the blade and the housing elements expand, which results in sliding between the platform and the housing element thereof in which it is fixed. The surface contact of two parts is currently designated “fretting” by the person skilled in the art. The more substantial the fretting is, the more the fatigue resistance of the parts is reduced.
In the engines according to the prior art, the fretting has no drawbacks given that the parts in contact are both metal and thus have comparable expansion factors.
In order to reduce the mass of an engine, it was proposed to replace the metal blades by blades made of composite material having fibres embedded in a matrix. When a platform of a blade made of composite material is in surface contact with a metal housing element, the matrix of the platform deteriorates and can cause oxidation of the fibres of the composite material. The service life and the performance of the blades made of composite material may then be impaired.